1. Field of the Invention
The present invention relates generally to coupling devices, and more particularly to a quick-disconnect coupling device for use in applications such as plug and receptacle style electrical connectors, fiberoptic connectors, pneumatic and hydraulic couplings or any other application where a secure quick-disconnect connection is desired.
2. Discussion of Related Art Including Information Disclosed Under 37 CFR §§ 1.97, 1.98
Quick-disconnect coupling devices are often used in applications requiring frequent coupling and decoupling, yet requiring a secure engagement due to the application environment having a probability of inadvertent forces being applied to the device being coupled. This can occur, for example, with a person tripping over a cord or hose, cabling catching on clothing, hoses or cables tangling with moving equipment, equipment being moved without first disconnecting the coupling and other similar situations and occurrences. Inadvertent disconnection is a concern in many applications where interruption of function would create hazardous conditions or have otherwise undesirable results or effects. For these reasons, there are many coupling devices that have secure latching systems to prevent such an inadvertent or accidental disconnect.
In some applications, another desire is an emergency release feature. This is a requirement in many stationary and mobile applications where personnel safety and equipment survival cannot be compromised. Some specific examples where personal injury could occur due to a non-releasing connection are helmet-to-equipment connections such as those found on police and civilian motorbikes for radio connections and for aircraft pilots that may need to hastily exit or eject from an aircraft. Worn-equipment configurations, often for communications or computer connections, exist within many applications including law enforcement, military infantry and special operations units, firefighting and other professions where interference with critical duties could be caused cables, hoses, tubes and the like, snagging or entangling with other objects. Examples of applications where equipment damage could occur include railroad railcar connections, towed vehicle connections and a multitude of others. These applications require the original secure coupling system plus an emergency release feature that will allow the coupling to disconnect at a selectable, predetermined force. In many applications it is important that the emergency release feature is a repeatable, consistent function and does not significantly degrade in release force for a large number of disconnect cycles over the lifetime of the installed equipment.
There have been numerous efforts to address these problems. A small sample of exemplary devices are shown in the following documents.
U.S. Pat. No. 5,021,002, to Noschese, shows a snap-lock electrical connector having an automatic disconnection feature. The electrical connector has a housing, a plurality of contacts, a snap-lock latch and a movable outer hood. The snap-lock latch can automatically mechanically connect and retain the housing to a second connector. The movable outer hood can be pulled by a user after connection which disconnects the latch and results in the disconnection of the electrical connector from the second connector.
U.S. Pat. No. 5,346,406, to Hoffman, et al., discloses an electrical cable and connector assembly having an electrical cable with power conductors and a pilot conductor releasably coupled to an electrical contact in an electrical connector, so that the pilot conductor releases from the electrical contact of the connector when a mechanical stress or force is applied to the cable. The power conductors are spirally wrapped about the centrally located pilot conductor so that the power conductors can stretch while the pilot conductor is pulled from its electrical contact upon application of the force or stress on the cable.
U.S. Pat. No. 6,146,188, to Snyder, teaches a shear connector includes a plug connector having front and rear insert portions on opposite sides of the shear plane that are held together by a shear bolt scored to shear at a predetermined force, and which is threaded directly into openings in the rear insert in such a way as to eliminate relative movement between the shear bolts and the rear insert during shearing. Pin contact sections extending rearwardly from the front insert are scored at the shear plane to shear at a predetermined force. By varying clearances between the pin contact sections and the sides of the openings of the rear insert into which the pin contact sections extend, groups of contacts can be made to shear at different times, thereby reducing the force required to shear each group without unduly weakening the contacts.
U.S. Pat. No. 6,511,341, to Finona, et al., shows a break-away apparatus for electrical and optical connectors having front and rear fittings with peripheries that have pairs of aligned fastener-receiving holes, and a plurality of fasteners that each lies in a pair of holes and holds the peripheries of the fittings together. Each fastener is a screw with a shank having a threaded front end that engages threads in the hole of the front fitting, and includes a screw head at the rear of the shank which lies against a rearwardly-facing shoulder on the rear fitting to prevent fitting separation. A bore extends along the axis of the shank, and a rear end portion of the shank has a groove, creating a break-away portion of the fastener that has a ring-shaped cross-section. The ring-shaped coss-section permits tightening of the screw but results in the screw breaking when a predetermined force is applied to allow separation of the fittings.
U.S. Pat. No. 427,542, to Gerow, discloses a connector that allows the connector main part to be pulled out of a coupling nut or part when the cable that extends rearwardly from the main part is pulled with a sufficiently large force. The main part is of the type that includes a metal shell enclosing an insulator that holds contacts whose front ends mate with the contacts of a mating connector device and whose rear ends connect to wires of the cable. The outside of the shell and the inside of the coupling part have adjacent grooves, and an expandable ring-shaped retainer lies in both grooves to normally hold the main part to the coupling part. The forward wall of the groove in the main part is inclined from an axial direction to form a ramp. If the main part is pulled rearwardly with a large force, the retainer expands as it rides up the ramp and past the front of the main part, to thereby release the main part from the coupling part and the connector device to which it is coupled.
U.S. Pat. No. 5,993,246, to Moldenhauer, et al., teaches a coupler for connecting a first element to a second element, including a first connector piece securable to the first element; a second connector piece for attaching to the first connector piece; and a flexible breakaway device mounted on the second element for releasably securing the second connector piece to the second element. A method of connecting and disconnecting a first element and a second element includes the steps of providing a first connector piece on the first element; attaching a breakaway device to the second element; attaching a second connector piece to the breakaway device that is attached to the second element; securing the first connector to the second connector; releasing the second connector piece from the second element by deflecting a portion of the breakaway device when a separation force is applied between the first and second elements.
U.S. Pat. No. 4,909,761, to Muguira, discloses an electric fuse holder having a cylindrical receiving body with an internally threaded nut attached in a manner that allows relative rotation between them. The assembly of the nut to the body allows separation of the nut from the body when a predetermined axial separating force is imparted between the parts, without damage to them. A second fuse receiving body has an external thread which engages the thread of the first body. As the threaded connection is made the body sections are drawn together to enclose the fuse.
FIGS. 1A and 1B schematically depicts an example of one of the many styles of the typical and well known quick-disconnect coupling systems. FIG. 1A shows the coupling system before disconnection, and FIG. 1B shows the coupling system during the disconnect action. The coupler consists of an inner latching sleeve 120 with cantilever beam latch-tabs 180, which are retracted by the sliding outer shell release sleeve 140 of the coupler plug. As the outer shell sleeve 140 is pulled axially with a force in direction F, the angled surface 185 of the latch tabs 180 causes them to retract toward the axis or center of the plug 195, withdrawing from the latch retaining groove 175 in the receptacle shell 170. As the operator continues to pull the outer shell 140, the latch tabs 180 bend as fully as necessary to drive the angled surface of the latch-tab interiorly and fully out of the retaining groove and the plug may be extracted from the receptacle 170 with relatively little resistance. Similar sliding release sleeve concepts are used with other locking schemes such as the ball detent and angled wedge type systems.
Still referring to FIGS. 1A and 1B, and stated summarily, existing coupling systems are designed to latch securely and prevent accidental disconnect due to pull on the cable 160 or any other object that is secured to the rear 110 of the coupler, or a pull applied directly to the rear of the coupler. The established approach to creating an emergency release feature is to reduce the retention force. This primary latching system is then subjected to forces and excessive abusive disconnects (such as cable pulls) that it was not intended to accommodate. This typically means variation and degradation of the retention force over time. Another very common approach is to raise the normal disconnect force of the primary latching system. One disadvantage of this is that the “normal” (intentional) disconnect force is higher than desired. Also, the higher forces employed can accelerate wear and variation over time.
The foregoing patents and typical prior art device reflect the current state of the art of which the present inventor is aware. Reference to, and discussion of, these patents and the illustrated device is intended to aid in discharging Applicant's acknowledged duty of candor in disclosing information that may be relevant to the examination of claims to the present invention. However, it is respectfully submitted that none of the above-indicated patents disclose, teach, suggest, show, or otherwise render obvious, either singly or when considered in combination, the invention described and claimed herein.